Issue 43

F. Berto et alii, Frattura ed Integrità Strutturale, 43 (2018) 1-32; DOI: 10.3221/IGF-ESIS.43.01 5 Figure 3: Synthesis of data taken from the literature. Different materials are summarized, among the others AISI O1 and duralluminium. Figure 4: Fatigue strength of welded joints as a function of the averaged local strain energy density; R is the nominal load ratio. where both λ 1 and e 1 depend on the V-notch angle. Eq. (5) makes it possible to estimate the R 0 value as soon as  1 N A K and Δ σ A are known. At N A = 5  10 6 cycles and in the presence of a nominal load ratio equal to zero a mean value  1 N A K 0.01 0.1 1.0 10 10 5 10 4 10 6 10 7 R 0 =0.28 mm 900 fatigue test data Various steels Inverse slope k=1.5 P.S. 97.7 % 2D, failure from the weld toe,  R = 0 2D, failure from the weld root,  R = 0 Butt welded joints -1 <  R < 0.2 3D, -1 <  R < 0.67 Hollow section joints, R = 0 Averaged strain energy density  W [Nmm/mm 3 ] T  W = 3.3 0.192 0.105 0.058 R 0 R 0 2  Cycles to failure, N 0 0.4 0.8 1.2 1.6 0.1 1 10 100 1000 ceramic materials PMMA data metallic materials and other materials  /R 0 About 1000 data from static tests 0.4  m  R 0  500  m 2.5   t  1200 MPa 0.15   IC  55 MPa m 0.5 0.1   0.4 0   /R 0  1000 0  2   150° Mode 1 and mixed mode (1+2) R  0 R 0 r 0 R R 0 +r 0 R 0 r 0 Steel AISI O1 Duralluminium PVC c W W Acrylic resin